It’s been 20 years of heartbreak and folly and mismanagement. Twenty years of bad calls and close calls. Twenty years of team after team and disappointment after disappointment.

And now, after all that waiting, the Rangers once again get the opportunity to play for the Stanley Cup.

By taking a 1-0 win over the Canadiens in Game 6 of the Eastern Conference finals on Thursday night at the Garden, the Blueshirts took possession of the Prince of Wales Trophy, victors of the conference. Serenaded with a chorus of “We want the Cup” by the Garden crowd, the Rangers now wait to see who comes out of the Kings-Blackhawks series to identify the final roadblock in this quest for the franchise’s second Cup in 74 years.

“I don’t think I’ve ever been more determined to win a hockey game,” said Henrik Lundqvist, The King when the Rangers needed him most.

The Rangers goalie had to face only 18 shots, but he turned them all away, overtaking Mike Richter on the franchise list with career postseason win No. 42, and tying Richter with postseason shutout No. 9.

Of course, Richter is a single link to that iconic squad of 1994, the most recent one that has come this close to the ultimate goal, and one that lives on in the city in perpetuity for bringing home the Cup and ending a 54-year championship drought. It is a place of rarefied air, one that would have seemed a pipe dream back when the Rangers were in a tailspin to start the season.

“In October?” coach Alain Vigneault said when he was asked what he would have thought had this scenario been given to him back then, when his first year behind the Blueshirts’ bench was looking like a disaster. “I probably would have said, ‘What are you smoking?’ ”

Vigneault’s comedy was a continued celebration from what had happened on the ice, as all the Rangers needed was a goal from Dominic Moore 18:07 into the second in order take this one, and send the Canadiens and all of their complaints that came with this series packing for the summer.

“You take pride in doing your job and doing it well,” Moore said. “Obviously, in big games like this, every little bit counts.”

Moore’s goal was the game-winner mostly because of the superb defensive play of his team, as Vigneault counted his team as having given up “one [scoring] chance in the first, four in the second, and nothing in the third.”

That, and one singular act of absolute brilliance from Lundqvist.

With 4:39 remaining in the second period, Lundqvist kept the game scoreless with a cartwheeling blocker save on Thomas Vanek, a stop that set 18,006 hearts aflutter with joy, their voices chanting down the ritualistic “Hen-rik” as if in thanks for a savior.

“That was the slowest-moving puck I’ve ever seen,” defenseman Marc Staal said. “Huge momentum right there. He makes that save, we score three minutes later, and we win.”

Henrik Lundqvist uses his pad to make a save in the second period.Photo: N.Y. Post: Charles Wenzelberg

And that win, how tenuous it seemed as the final minutes and seconds ticked down. The Rangers had a handful of chances to get that second goal, and they just couldn’t solve rookie goalie Dustin Tokarski once more.

So instead there was Ryan McDonagh, the pressure of a one-goal lead finally beginning to release as he held the puck in the corner of his own zone, the clock going from five to four to three. He tossed it up the left boards, the horn sounded, and red-white-and-blue streamers came raining down from the rafters.

“When it’s only two or three seconds left and you realize you did it,” Lundqvist said, “it’s an unbelievable feeling.”

Believe it or not, this also happened to be the exact day one year ago that John Tortorella was fired. How much things have changed, as the Rangers now have until Wednesday to prepare for Game 1 of the Stanley Cup final, either in Los Angeles or Chicago.

“You never know what can happen in a year,” said de facto captain Brad Richards, one of two players dressed who has been in this spot before, and who instructed his teammates not to touch the Prince of Wales Trophy, as a much more meaningful prize awaits.

“There were some down moments this year, to be honest,” Richards said. “We lost it, we kept battling, and figured it out. We figured it out to get a chance to win the Cup.”

Henrik Lundqvist celebrates after helping defeat the Montreal Canadiens in Game 6 of the Eastern Conference Final.Photo: Getty Images